A Survey of Ant Species in Three Habitats at Mount St. Helens National Volcanic Monument

Table 7

Mann-Whitney U tests comparing plant community characteristics between habitat types at Mount St. Helens National Volcanic Monument.

Plant community characteristic	Habitat type* comparison	Mann-Whitney U test statistic	𝑃^∗∗
Plant richness	BDZ > PPLV	99	0.0014
	PPHV > PPLV	36	0.0009
	BDZ = PPHV	51	0.0754
Percent ground cover by plants	BDZ > PPLV	99.5	0.0011
	PPHV > PPLV	36	0.0006
	BDZ = PPHV	51	0.0809

* PPLV: Pumice Plain-Low Vegetation, PPHV: Pumice Plain-High Vegetation, BDZ: Blowdown Zone.
**With a Bonferroni correction, only P values < 0.017 were considered significant.